Methods and systems for ARQ feedback message improvement

CLAIM OF PRIORITY

p-0002This patent application claims the benefit of priority from U.S. Provisional Patent Application Ser. No. 61/112,147, entitled “Improvement of ARQ Feedback Message” and filed Nov. 6, 2008, which is assigned to the assignee of this application and is fully incorporated herein by reference for all purposes.

TECHNICAL FIELD

p-0003The present disclosure generally relates to wireless communications, and more specifically, to improving automatic repeat request (ARQ) feedback messages to reduce unnecessary retransmissions.

BACKGROUND

p-0004Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.

p-0005Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-input-single-output, multiple-input-single-output or a multiple-input-multiple-output (MIMO) system.

p-0006A MIMO system employs multiple (N_T) transmit antennas and multiple (N_R) receive antennas for data transmission. A MIMO channel formed by the N_Ttransmit and N_Rreceive antennas may be decomposed into N_Sindependent channels, which are also referred to as spatial channels, where N_S≦min {N_T, N_R}. Each of the N_Sindependent channels corresponds to a dimension. The MIMO system can provide improved performance (e.g., higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.

SUMMARY

p-0007Certain embodiments of the present disclosure provide a method for wireless communications. The method generally includes receiving an Automatic Repeat-Request (ARQ) feedback message, determining a last block acknowledged based on the ARQ feedback message, and ignoring one or more bits in the ARQ feedback message after the last block acknowledged.

p-0008Certain embodiments of the present disclosure provide a method for wireless communications. The method generally includes receiving an Automatic Repeat-Request (ARQ) block, generating an ARQ feedback message including an indication of a last block acknowledged from the ARQ block, and transmitting the ARQ feedback message.

p-0009Certain embodiments of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes logic for receiving an Automatic Repeat-Request (ARQ) feedback message, logic for determining a last block acknowledged based on the ARQ feedback message, and logic for ignoring one or more bits in the ARQ feedback message after the last block acknowledged.

p-0010Certain embodiments of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes logic for receiving an Automatic Repeat-Request (ARQ) block, logic for generating an ARQ feedback message including an indication of a last block acknowledged from the ARQ block, and logic for transmitting the ARQ feedback message.

p-0011Certain embodiments of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes means for receiving an Automatic Repeat-Request (ARQ) feedback message, means for determining a last block acknowledged based on the ARQ feedback message, and means for ignoring one or more bits in the ARQ feedback message after the last block acknowledged.

p-0012Certain embodiments of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes means for receiving an Automatic Repeat-Request (ARQ) block, means for generating an ARQ feedback message including an indication of a last block acknowledged from the ARQ block, and means for transmitting the ARQ feedback message.

p-0013Certain embodiments of the present disclosure provide a computer-program storage apparatus for wireless communications, comprising a computer readable medium having instructions stored thereon, the instructions being executable by one or more processors. The instructions generally include instructions for receiving an Automatic Repeat-Request (ARQ) feedback message, instructions for determining a last block acknowledged based on the ARQ feedback message, and instructions for ignoring one or more bits in the ARQ feedback message after the last block acknowledged.

p-0014Certain embodiments of the present disclosure provide a computer-program storage apparatus for wireless communications, comprising a computer readable medium having instructions stored thereon, the instructions being executable by one or more processors. The instructions generally include instructions for receiving an Automatic Repeat-Request (ARQ) block, instructions for generating an ARQ feedback message including an indication of a last block acknowledged from the ARQ block, and instructions for transmitting the ARQ feedback message.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0015Aspects and embodiments of the disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout.

p-0016<figref idrefs="DRAWINGS">FIG. 1</figref> illustrates an exemplary wireless communication system in accordance with certain embodiments set forth herein;

p-0017<figref idrefs="DRAWINGS">FIG. 2</figref> illustrates a block diagram of a communication system in accordance with certain embodiments set forth herein;

p-0018<figref idrefs="DRAWINGS">FIG. 3</figref> illustrates automatic repeat request (ARQ) feedback message types according to the mobile Worldwide Interoperability for Microwave Access (WiMAX) standard;

p-0019<figref idrefs="DRAWINGS">FIG. 4</figref> illustrates an exemplary send/receive timeline for an ARQ feedback message.

p-0020<figref idrefs="DRAWINGS">FIG. 5</figref> illustrates an exemplary feedback bitmap for a selective ARQ feedback for the example in <figref idrefs="DRAWINGS">FIG. 4</figref>;

p-0021<figref idrefs="DRAWINGS">FIG. 6</figref> illustrates example operations performed by an ARQ transmitter, in accordance with certain embodiments as set forth herein;

p-0022<figref idrefs="DRAWINGS">FIG. 6A</figref> illustrates example components capable of performing the operations illustrated in <figref idrefs="DRAWINGS">FIG. 6</figref>;

p-0023<figref idrefs="DRAWINGS">FIG. 7</figref> illustrates an exemplary exchange of commands between an ARQ transmitter and an ARQ receiver, and example operations performed by the ARQ transmitter and the ARQ receiver, in accordance with certain embodiments as set forth herein;

p-0024<figref idrefs="DRAWINGS">FIG. 7A</figref> illustrates example components capable of performing the operations illustrated in <figref idrefs="DRAWINGS">FIG. 7</figref>;

p-0025<figref idrefs="DRAWINGS">FIG. 8</figref> illustrates a first set of proposed bitmaps for selective ARQ feedback and cumulative with selective ARQ feedback messages, in accordance with certain embodiments as set forth herein;

p-0026<figref idrefs="DRAWINGS">FIG. 9</figref> illustrates a second set of proposed bitmaps for selective ARQ feedback and cumulative with selective ARQ feedback messages, in accordance with certain embodiments as set forth herein;

p-0027<figref idrefs="DRAWINGS">FIG. 10</figref> illustrates an exemplary exchange of commands between an ARQ transmitter and an ARQ receiver, and example operations performed by the ARQ transmitter and the ARQ receiver, in accordance with certain embodiments as set forth herein;

p-0028<figref idrefs="DRAWINGS">FIG. 10A</figref> illustrates example components capable of performing the operations illustrated in <figref idrefs="DRAWINGS">FIG. 10</figref>; and

p-0029<figref idrefs="DRAWINGS">FIGS. 11A-11D</figref> illustrate a third set of proposed bitmaps for selective ARQ feedback and cumulative with selective ARQ feedback messages, in accordance with certain embodiments as set forth herein.

DETAILED DESCRIPTION

p-0030Certain embodiments are described herein with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of certain embodiments. However, it may be that such embodiment(s) can be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing certain embodiments.

h-0007Exemplary Wireless Communication System

p-0031The techniques described herein may be used for various broadband wireless communication systems, including communication systems that are based on an orthogonal multiplexing scheme. Examples of such communication systems include Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single-Carrier Frequency Division Multiple Access (SC-FDMA) systems, and so forth. An OFDMA system utilizes orthogonal frequency division multiplexing (OFDM), which is a modulation technique that partitions the overall system bandwidth into multiple orthogonal sub-carriers. These sub-carriers may also be called tones, bins, etc. With OFDM, each sub-carrier may be independently modulated with data. An SC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit on sub-carriers that are distributed across the system bandwidth, localized FDMA (LFDMA) to transmit on a block of adjacent sub-carriers, or enhanced FDMA (EFDMA) to transmit on multiple blocks of adjacent sub-carriers. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDMA.

p-0032One example of a communication system based on an orthogonal multiplexing scheme is a WiMAX system. WiMAX, which stands for the Worldwide Interoperability for Microwave Access, is a standards-based broadband wireless technology that provides high-throughput broadband connections over long distances. There are two main applications of WiMAX today: fixed WiMAX and mobile WiMAX. Fixed WiMAX applications are point-to-multipoint, enabling broadband access to homes and businesses, for example. Mobile WiMAX is based on OFDM and OFDMA and offers the full mobility of cellular networks at broadband speeds.

p-0033IEEE 802.16x is an emerging standard organization to define an air interface for fixed and mobile broadband wireless access (BWA) systems. These standards define at least four different physical layers (PHYs) and one media access control (MAC) layer. The OFDM and OFDMA physical layer of the four physical layers are the most popular in the fixed and mobile BWA areas respectively.

p-0034<figref idrefs="DRAWINGS">FIG. 1</figref> illustrates an exemplary wireless communication system <b>100</b> in accordance with certain embodiments set forth herein. Wireless communication system <b>100</b> may be a broadband wireless communication system. The term “broadband wireless” refers to technology that at least provides wireless, audio, video, voice, Internet, and/or data network access. Wireless communication system <b>100</b> provides communication for one or more cells <b>102</b>, each of which is serviced by a base station <b>104</b>. Base station <b>104</b> may be a fixed station that communicates with user terminals <b>106</b> within cell <b>102</b> serviced by that base station <b>104</b>. Base station <b>104</b> may alternatively be referred to as an access point, Node B or some other terminology.

p-0035As shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, various user terminals <b>106</b> dispersed throughout wireless communication system <b>100</b>. User terminals <b>106</b> may be fixed (i.e., stationary), mobile or capable of both. User terminals <b>106</b> may alternatively be referred to as remote stations, access terminals, terminals, subscriber units, mobile stations, stations, user equipment and the like. User terminals <b>106</b> may be personal wireless devices, such as cellular phones, personal digital assistants (PDAs), handheld devices, wireless modems, audio/video players, laptop computers, personal computers, other handheld communication devices, other handheld computing devices, satellite radios, global positioning systems, and so on. A variety of algorithms and methods may be used for transmissions in wireless communication system <b>100</b> between base stations <b>104</b> and user terminals <b>106</b>. For example, signals may be sent and received between base stations <b>104</b> and user terminals <b>106</b> in accordance with OFDM/OFDMA techniques. If this is the case, wireless communication system <b>100</b> may be referred to as an OFDM/OFDMA system <b>100</b>.

p-0036A communication link that facilitates transmission from base station <b>104</b> to user terminal <b>106</b> may be referred to as a downlink <b>108</b>, and a communication link that facilitates transmission from user terminal <b>106</b> to base station <b>104</b> may be referred to as an uplink <b>110</b>. Alternatively, downlink <b>108</b> may be referred to as a forward link or a forward channel, and uplink <b>110</b> may be referred to as a reverse link or a reverse channel. Cell <b>102</b> may be divided into multiple sectors <b>112</b>. Sector <b>112</b> is a physical coverage area within cell <b>102</b>. Base stations <b>104</b> within an OFDM/OFDMA system <b>100</b> may utilize antennas that concentrate the flow of power within a particular sector <b>112</b> of the cell <b>102</b>. Such antennas may be referred to as directional antennas.

p-0037In certain embodiments, system <b>100</b> can be a multiple-input multiple-output (MIMO) communication system. Further, system <b>100</b> can utilize substantially any type of duplex technique to divide communication channels (e.g., forward link <b>108</b>, reverse link <b>110</b>, etc.) such as FDD, TDD, and the like. The channels can be provided for transmitting control data between mobile devices <b>106</b> and respective base stations <b>104</b>.

p-0038<figref idrefs="DRAWINGS">FIG. 2</figref> illustrates an exemplary wireless network environment <b>200</b> in accordance with certain embodiments set forth herein. Wireless network environment <b>200</b> depicts one base station <b>210</b> and one mobile device <b>250</b> for sake of brevity. However, it is contemplated that system <b>200</b> can include one or more base stations and/or one or more mobile devices, wherein additional base stations and/or mobile devices can be substantially similar or different from illustrated base station <b>210</b> and illustrated mobile device <b>250</b> described herein. In addition, it is contemplated that base station <b>210</b> and/or mobile device <b>250</b> can employ the systems, techniques, configurations, embodiments, aspects, and/or methods described herein to facilitate wireless communication between them.

p-0039At base station <b>210</b>, traffic data for a number of data streams is provided from a data source <b>212</b> to a transmit (TX) data processor <b>214</b>. In certain embodiments, each data stream can be transmitted over a respective antenna and/or over multiple antennas. TX data processor <b>214</b> formats, codes, and interleaves the traffic data stream based on a particular coding scheme selected for that data stream to provide coded data.

p-0040The coded data for each data stream can, for example, be multiplexed with pilot data using orthogonal frequency division multiplexing (OFDM) techniques. Additionally or alternatively, the pilot symbols can be frequency division multiplexed (FDM), time division multiplexed (TDM), or code division multiplexed (CDM). The pilot data is typically a known data pattern that is processed in a known manner and can be used at mobile device <b>250</b> to estimate channel response or other communication parameters and/or characteristics. The multiplexed pilot and coded data for each data stream can be modulated (e.g., symbol mapped) based on a particular modulation scheme (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM), etc.) selected for that data stream to provide modulation symbols. The data rate, coding and modulation for each data stream can be determined by instructions performed or provided by processor <b>230</b>.

p-0041The modulation symbols for the data streams can be provided to a TX MIMO processor <b>220</b>, which can further process the modulation symbols (e.g., for OFDM). TX MIMO processor <b>220</b> then provides Nt modulation symbol streams to Nt transmitters (TMTR) <b>222</b><i>a </i>through <b>222</b><i>t</i>. In certain embodiments, TX MIMO processor <b>220</b> applies certain multi-antenna techniques, such spatial multiplexing, diversity coding or precoding (i.e., beamforming, with weights being applied to the modulation symbols of the data streams and to the antenna from which the symbol is being transmitted).

p-0042Each transmitter <b>222</b> receives and processes a respective modulation symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, upconverts, etc.) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. Further, Nt modulated signals from transmitters <b>222</b><i>a </i>through <b>222</b><i>t </i>are transmitted from Nt antennas <b>224</b><i>a </i>through <b>224</b><i>t</i>, respectively.

p-0043At mobile device <b>250</b>, the transmitted modulated signals are received by Nr antennas <b>252</b><i>a </i>through <b>252</b><i>r </i>and the received signal from each antenna <b>252</b> is provided to a respective receiver (RCVR) <b>254</b><i>a </i>through <b>254</b><i>r</i>. Each receiver <b>254</b> conditions (e.g., filters, amplifies, downconverts, etc.) a respective signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

p-0044A receive (RX) data processor <b>260</b> can receive and process the Nr received symbol streams from Nr receivers <b>254</b> based on a particular receiver processing technique to provide Nt “detected” symbol streams. RX data processor <b>260</b> can demodulate, deinterleave, and decode each detected symbol stream to recover the traffic data for the data stream, and provide the traffic data to a data sink <b>262</b>. In certain embodiments, for mobile device <b>250</b>, the processing by RX data processor <b>260</b> can be complementary to that performed by TX MIMO processor <b>220</b> and TX data processor <b>214</b> at base station <b>210</b>.

p-0045A processor <b>270</b> can periodically determine which precoding matrix to utilize as discussed above. Further, processor <b>270</b> can formulate a reverse link message comprising a matrix index portion and a rank value portion. The reverse link message can comprise various types of information regarding the communication link and/or the received data stream. The reverse link message can be processed by a TX data processor <b>238</b>, which also receives traffic data for a number of data streams from a data source <b>236</b>, modulated by a modulator <b>280</b>, conditioned by transmitters <b>254</b><i>a </i>through <b>254</b><i>r</i>, and transmitted back to base station <b>210</b>.

p-0046At base station <b>210</b>, the modulated signals from mobile device <b>250</b> are received by Nt antennas <b>224</b>, conditioned by respective Nt receivers <b>222</b>, demodulated by a demodulator <b>240</b>, and processed by a RX data processor <b>242</b> to extract the reverse link message transmitted by mobile device <b>250</b>, and provide the reverse link message to a data sink <b>244</b>. Further, processor <b>230</b> can process the extracted message to determine which precoding matrix to use for determining the beamforming weights.

p-0047Processors <b>230</b> and <b>270</b> can direct (e.g., control, coordinate, manage, etc.) operation at base station <b>210</b> and mobile device <b>250</b>, respectively. Respective processors <b>230</b> and <b>270</b> can be associated with memory <b>232</b> and <b>272</b> that store program codes and data. Processors <b>230</b> and <b>270</b> can also perform computations to derive frequency and impulse response estimates for the uplink and downlink, respectively. All “processor” functions can be migrated between and among process modules such that certain processor modules may not be present in certain embodiments, or additional processor modules not illustrated herein may be present.

p-0048Memory <b>232</b> and <b>272</b> (as with all data stores disclosed herein) can be either volatile memory or nonvolatile memory or can include both volatile and nonvolatile portions, and can be fixed, removable or include both fixed and removable portions. By way of illustration, and not limitation, nonvolatile memory can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable PROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink™ DRAM (SLDRAM), and direct Rambus™ RAM (DRRAM).

h-0008Exemplary Improvement of ARQ Feedback Messages

p-0049Certain embodiments of the present disclosure propose methods for improving automatic repeat request (ARQ) feedback messages. The methods include notifying the ARQ transmitter of the last block acknowledged in a ARQ feedback message to avoid unnecessary retransmissions.

p-0050In the Mobile WiMAX standards four types of ARQ feedback messages are defined, such as type one (00): Selective acknowledgement (ACK), type two (01): Cumulative ACK, type three (10): Cumulative with Selective ACK, and type four (11): Cumulative ACK with Block Sequence ACK.

p-0051<figref idrefs="DRAWINGS">FIG. 3</figref> illustrates ARQ feedback message types according to the mobile WiMAX standard. In this figure, bitmaps are shown for the four ARQ feedback message types. CID <b>302</b> is a 16-bit connection identification, BSN <b>304</b> is the block serial number, L <b>306</b> shows the last bit, N <b>308</b> shows number of ACK MAP information elements (IEs) minus one, X <b>310</b> is a bit with a value of either zero or one, and Seq Len <b>312</b> shows the sequence length.

p-0052Generally, an ARQ receiver utilizing the Selective ACK or the Cumulative with Selective ACK feedback message types should prepare bitmaps with blocks in multiples of 16. A problem may arise if the ARQ receiver needs to provide ARQ feedback showing ACK for blocks totaling a number different from a multiple of 16. For example, the receiver may want to send ACK messages for 9 blocks. Therefore, the ARQ receiver has to prepare the ARQ feedback with the bits corresponding to the additional blocks set as NACK to bring the total number of bits in a feedback block to a multiple of 16. For example, the ARQ receiver may need to add 16−9=7 zeros (e.g., NACK) to the ARQ feedback message to generate a 16-bit ARQ feedback message. Therefore, the ARQ receiver may generate more NACKs than necessary, which may result in unnecessary retransmissions by the ARQ transmitter.

p-0053<figref idrefs="DRAWINGS">FIG. 4</figref> illustrates an example send/receive timeline for an ARQ feedback message. In the first frame <b>402</b> (e.g., frame <b>1</b>), the ARQ receiver receives an ARQ block (e.g., block <b>10</b>). The ARQ receiver prepares a selective feedback message (e.g., feedback message <b>1</b>). In the second frame <b>404</b> (e.g., frame <b>2</b>), the ARQ receiver receives a second ARQ block (e.g., block <b>11</b>), in addition, the ARQ receiver receives bandwidth to send the feedback message for the previous block (e.g., feedback message <b>1</b>) in the third frame <b>406</b> (e.g., frame <b>3</b>).

p-0054<figref idrefs="DRAWINGS">FIG. 5</figref> illustrates an example selective feedback message for the first frame <b>402</b> in <figref idrefs="DRAWINGS">FIG. 4</figref>. The feedback message <b>1</b> includes an ACK bit <b>502</b> for the first frame (block <b>10</b>) and NACK bits for frames after the first frame, including the block <b>11</b> received in the second frame.

p-0055In the third frame <b>406</b> (e.g., frame <b>3</b> in <figref idrefs="DRAWINGS">FIG. 4</figref>), the ARQ transmitter receives the selective feedback message <b>1</b>, which shows a NACK bit <b>504</b> for the block <b>11</b> (as illustrated in <figref idrefs="DRAWINGS">FIG. 5</figref>). In response to the NACK message for the block <b>11</b>, the ARQ transmitter resends the block <b>11</b>, which may not be necessary, since it was just sent in the previous frame and might have been received correctly.

p-0056Certain embodiments of the present disclosure propose methods for reducing unnecessary negative acknowledgement which result in unnecessary retransmissions of the blocks by an ARQ transmitter, by notifying the transmitter of the last acknowledged bit in the ARQ feedback message.

p-0057<figref idrefs="DRAWINGS">FIG. 6</figref> illustrates an example sequence of operations performed by an ARQ transmitter, according to certain embodiments of the present application. At <b>602</b>, the ARQ transmitter receives an ARQ feedback with respect to blocks sent. At <b>604</b>, the ARQ transmitter identifies the last ACK bit in the ARQ feedback message. At <b>606</b>, the ARQ transmitter ignores consecutive NACK bits after the last ACK bit. By ignoring the consecutive NACK bits after the last ACK bit, according to certain embodiments, the ARQ transmitter avoids unnecessary retransmissions.

p-0058<figref idrefs="DRAWINGS">FIG. 7</figref> illustrates an example exchange of commands and sequences of operations performed by an ARQ transmitter and an ARQ receiver, according to certain embodiments of the present application. The ARQ transmitter transmits blocks, shown at <b>702</b>, which are received at least in part by the ARQ receiver, shown at <b>704</b>. The ARQ receiver generates a feedback message (including an ACK MAP) at <b>706</b>. For example, the ARQ receiver may utilize any of the feedback message bitmaps in <figref idrefs="DRAWINGS">FIGS. 8 and 9</figref>. The ARQ receiver then sends the ARQ feedback message with an indication of the last block acknowledged in the ACK MAP, shown at <b>708</b>.

p-0059The ARQ transmitter receives the ARQ feedback message with the indication of the last block acknowledged in the ACK MAP information element, shown at <b>710</b>. The ARQ transmitter ignores the bits in the ACK MAP after the bit corresponding to the last block acknowledged, shown at <b>712</b>. The ARQ transmitter may retransmit some of the blocks based on the ACK or NACK bits received in the valid portion of the ACK MAP.

p-0060<figref idrefs="DRAWINGS">FIG. 8</figref> illustrates a first set of proposed bitmaps for selective ARQ feedback and cumulative with selective ARQ feedback messages, in accordance with certain embodiments of <figref idrefs="DRAWINGS">FIG. 7</figref> and the present application. As shown in <figref idrefs="DRAWINGS">FIG. 8</figref>, the ACK MAP may include indication of the last block serial number (BSN) <b>802</b> the receiver wants to acknowledge.

p-0061<figref idrefs="DRAWINGS">FIG. 9</figref> illustrates a second set of proposed bitmaps for selective ARQ feedback and cumulative with selective ARQ feedback messages, in accordance with certain embodiments of <figref idrefs="DRAWINGS">FIG. 7</figref> and the present application. As shown in <figref idrefs="DRAWINGS">FIG. 9</figref>, the last four bits <b>902</b> of the last ACK MAP block <b>904</b> may indicate which bit is the last valid bit. In the example of <figref idrefs="DRAWINGS">FIG. 9</figref>, the last ACK MAP block <b>904</b> may indicate up to a maximum of twelve acknowledged blocks (e.g., twelve ACK bits), as the remaining four bits are used to indicate which bit is the last valid bit.

p-0062For certain embodiments of the present disclosure, in order to reduce the unnecessary retransmissions, the ARQ transmitter may be notified of the last acknowledged block by a block containing the serial number of the last block acknowledged, if the last bit in the last ACK MAP block is zero. If the last bit in the last ACK MAP block is one, meaning that the last block is acknowledged, the ARQ transmitter does not wait to receive another block containing the serial number of the last block acknowledged.

p-0063<figref idrefs="DRAWINGS">FIG. 10</figref> illustrates an example exchange of commands and sequences of operations performed by an ARQ transmitter and an ARQ receiver, according to certain embodiments of the present application. The ARQ transmitter transmits blocks, shown at <b>1002</b>, which are received at least in part by the ARQ receiver, shown at <b>1004</b>. The ARQ receiver generates ARQ feedback messages (ACK MAPs) at <b>1006</b>. The ARQ receiver then sends the ARQ feedback message with the last bit in the last ACK MAP indicating whether or not a “last block acknowledged” field is included in the ARQ feedback message, shown at <b>1008</b>.

p-0064The ARQ transmitter receives the ARQ feedback at <b>1010</b>. The ARQ transmitter reads the last bit in the last ACK MAP, at <b>1012</b>. If the last bit in the last ACK MAP is one, the ARQ transmitter interprets the last bit as ACK, shown at <b>1014</b>. If the last bit in the last ACK Map is zero, the ARQ transmitter gets and reads the serial number of the last block acknowledged in the last block acknowledged field, shown at <b>1016</b>. The ARQ transmitter then ignores the bits in the last ACK MAP message after the bit associated with the last block acknowledged.

p-0065<figref idrefs="DRAWINGS">FIGS. 11A-11D</figref> illustrate a third set of proposed bitmaps for selective ARQ feedback and cumulative with selective ARQ feedback messages, in accordance with certain embodiments of <figref idrefs="DRAWINGS">FIG. 10</figref> and the present application. The last ACK MAP block <b>904</b> in the ARQ feedback message has a value of either zero or one for the last bit.

p-0066<figref idrefs="DRAWINGS">FIG. 11A</figref> illustrates the proposed bitmap for selective ARQ feedback when the last bit <b>1102</b> in the last ACK MAP block <b>904</b> is zero. Therefore, an additional block is received by the transmitter that includes the serial number of the last block acknowledged <b>802</b> in the last ACK MAP block.

p-0067<figref idrefs="DRAWINGS">FIG. 11B</figref> illustrates the proposed bitmap for selective ARQ feedback when the last bit <b>1102</b> in the last ACK MAP block <b>904</b> is one, Therefore, the ARQ transmitter interprets this bit as an ACK for the block corresponding to the last bit <b>1102</b> in the last ACK MAP block <b>904</b>.

p-0068<figref idrefs="DRAWINGS">FIG. 11C</figref> illustrates the proposed bitmap for cumulative with selective ARQ feedback when the last bit <b>1102</b> in the last ACK MAP block <b>904</b> is zero. Similar to <figref idrefs="DRAWINGS">FIG. 11A</figref>, an additional block is received by the transmitter that includes the serial number of the last block acknowledged <b>802</b> in the last ACK MAP block.

p-0069<figref idrefs="DRAWINGS">FIG. 11D</figref> illustrates the proposed bitmap for cumulative with selective ARQ feedback when the last bit <b>1102</b> in the last ACK MAP block <b>904</b> is one. Similar to <figref idrefs="DRAWINGS">FIG. 11D</figref>, ACK is indicated for the block corresponding to the last bit <b>1102</b> in the last ACK MAP block <b>904</b>.

p-0070Certain embodiments of the present disclosure provided methods to notify the ARQ transmitter of the last block acknowledged in the ARQ feedback message in order to avoid unnecessary retransmissions. Information regarding the last block acknowledged may be sent to the ARQ transmitter in various forms. The present disclosure lists a few example bitmaps for selective and cumulative with selective feedback containing information about last acknowledged block. However, other bitmaps may be used without departing from the scope of the current disclosure.

p-0071The various operations of methods described above may be performed by various hardware and/or software component(s) and/or module(s) corresponding to means-plus-function blocks illustrated in the Figures. Generally, where there are methods illustrated in Figures having corresponding counterpart means-plus-function Figures, the operation blocks correspond to means-plus-function blocks with similar numbering. For example, operations <b>600</b>, <b>700</b> and <b>1000</b> illustrated in <figref idrefs="DRAWINGS">FIGS. 6</figref>, <b>7</b> and <b>10</b> all correspond to means-plus-function blocks <b>600</b>A, <b>700</b>A, and <b>1000</b>A illustrated in <figref idrefs="DRAWINGS">FIGS. 6A</figref>, <b>7</b>A and <b>10</b>A.

p-0072As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

p-0073Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals and the like that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles or any combination thereof.

p-0074The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array signal (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core or any other such configuration.

p-0075The steps of a method or algorithm described in connection with the present disclosure may be embodied directly in hardware, in a software module executed by a processor or in a combination of the two. A software module may reside in any form of storage medium that is known in the art. Some examples of storage media that may be used include RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM and so forth. A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs and across multiple storage media. A storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.

p-0076The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

p-0077The functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions on a computer-readable medium. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.

p-0078Software or instructions may also be transmitted over a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of transmission medium.

p-0079Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein, such as those illustrated in the Figures, can be downloaded and/or otherwise obtained by a mobile device and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via a storage means (e.g., random access memory (RAM), read only memory (ROM), a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a mobile device and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

p-0080It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims

p-0081While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.